bac-s-maths 2019 Q1A

bac-s-maths · France · amerique-sud Exponential Distribution
Let $T$ denote the random variable equal to the lifespan, in months, of a stopwatch and we assume it follows an exponential distribution with parameter $\lambda = 0.0555$.
  1. Calculate the average lifespan of a stopwatch (rounded to the nearest unit).
  2. Calculate the probability that a stopwatch has a lifespan between one and two years.
  3. A coach has not changed his stopwatch for two years. What is the probability that it will still be in working order for at least one more year?
Let $T$ denote the random variable equal to the lifespan, in months, of a stopwatch and we assume it follows an exponential distribution with parameter $\lambda = 0.0555$.

\begin{enumerate}
  \item Calculate the average lifespan of a stopwatch (rounded to the nearest unit).
  \item Calculate the probability that a stopwatch has a lifespan between one and two years.
  \item A coach has not changed his stopwatch for two years. What is the probability that it will still be in working order for at least one more year?
\end{enumerate}